Fix a simple spelling error 'occured' -> 'occurred' (#3737)

* Firestore Externs: @type -> @typedef

* Fix spelling

Author: richieforeman

packages/messaging/src/util/errors.ts

@@ -53,14 +53,14 @@ export const ERROR_MAP: ErrorMap<ErrorCode> = {
   [ErrorCode.FAILED_DEFAULT_REGISTRATION]:
     'We are unable to register the default service worker. {$browserErrorMessage}',
   [ErrorCode.TOKEN_SUBSCRIBE_FAILED]:
-    'A problem occured while subscribing the user to FCM: {$errorInfo}',
+    'A problem occurred while subscribing the user to FCM: {$errorInfo}',
   [ErrorCode.TOKEN_SUBSCRIBE_NO_TOKEN]:
     'FCM returned no token when subscribing the user to push.',
   [ErrorCode.TOKEN_UNSUBSCRIBE_FAILED]:
-    'A problem occured while unsubscribing the ' +
+    'A problem occurred while unsubscribing the ' +
     'user from FCM: {$errorInfo}',
   [ErrorCode.TOKEN_UPDATE_FAILED]:
-    'A problem occured while updating the user from FCM: {$errorInfo}',
+    'A problem occurred while updating the user from FCM: {$errorInfo}',
   [ErrorCode.TOKEN_UPDATE_NO_TOKEN]:
     'FCM returned no token when updating the user to push.',
   [ErrorCode.USE_SW_AFTER_GET_TOKEN]:

packages/rxfire/docs/database.md

@@ -121,7 +121,7 @@ ref.push({ name: 'David' });
 
 stateChanges(ref).subscribe(change => {
   const { event, snapshot, prevKey } = change;
-  console.log(event, ' the event type that just occured');
+  console.log(event, ' the event type that just occurred');
   console.log(snapshot.val(), ' the value of the change');
 });
 

packages/rxfire/docs/firestore.md

@@ -145,7 +145,7 @@ collectionChanges(collectionRef, ['added'])
 ```
 
 ### `sortedChanges()`
-The `sortedChanges()` function creates an observable that emits the reduced state of individual changes. This is different than the collection function in that it creates an array out of every individual change to occur. It also contains the `type` property to indicate what kind of change occured. The optional `events` parameter will filter which child events populate the array.
+The `sortedChanges()` function creates an observable that emits the reduced state of individual changes. This is different than the collection function in that it creates an array out of every individual change to occur. It also contains the `type` property to indicate what kind of change occurred. The optional `events` parameter will filter which child events populate the array.
 
 |                 |                                          |
 |-----------------|------------------------------------------|

packages/rxfire/test/firestore.test.ts

@@ -216,7 +216,7 @@ describe('RxFire Firestore', () => {
   describe('auditTrail', () => {
     /**
      * The `auditTrail()` method returns an array of every change that has
-     * occured in the application. This test seeds two "people" into the
+     * occurred in the application. This test seeds two "people" into the
      * collection and checks that the two added events are there. It then
      * modifies a "person" and makes sure that event is on the array as well.
      */
@@ -265,7 +265,7 @@ describe('RxFire Firestore', () => {
   describe('auditTrail', () => {
     /**
      * The `auditTrail()` method returns an array of every change that has
-     * occured in the application. This test seeds two "people" into the
+     * occurred in the application. This test seeds two "people" into the
      * collection and checks that the two added events are there. It then
      * modifies a "person" and makes sure that event is on the array as well.
      */